The present invention relates to an address management system, an interface ID setting processor, a communication terminal, an address management method, and a computer program. More specifically, the present invention relates to an address management system, an interface ID setting processor, a communication terminal, an address management method, and a computer program, in which an interface ID in the Internet Protocol version 6 (IPv6) can be smoothly received and transmitted between apparatuses.
In recent years, mobile personal computers and mobile phones have been widely used. Many users carry these compact communication terminals which have a communication function and information processing function, and communicate through a network by connecting to the network at remote locations away from their homes.
In the Internet, an internet protocol (IP) is used as a communication protocol. The IP which is most commonly used now is IPv4, and a 32-bit address (IP address) is used as the address of the sender and the destination. In the Internet communication, a global IP address, in which a 32-bit IP address is uniquely allocated to each sender and destination, is adopted and individual senders and destinations are identified based on the IP addresses. However, the Internet has been expanding rapidly and the limited address space of IPv4, that is, the exhaustion of global addresses has become a problem. In order to solve the problem, the Internet Engineering Task Force (IETF) has proposed a new Internet Protocol version 6 (IPv6) as a next-generation IP address, in which the IP address space is expanded from 32 bits to 128 bits.
The IPv6 is a successor protocol of the current IPv4 and has the address format shown in FIG. 1. The IPv6 has a 128-bit configuration. The lower bits correspond to an interface ID (for example, IEEE 802 format) as a node identifier for uniquely identifying nodes on the Internet or a subnetwork, and the upper bits correspond to a network prefix as a location indicator for indicating the subnetwork to which the node is connected. Accordingly, the terminals connected to the same subnetwork have basically the same network prefix of the upper bits in the IPv6 address.
In the IPv6, since packets are transmitted based on only a prefix and a subnet number, the lower bits of the address, that is, the interface ID, can be allotted by a terminal manufacturer. Properly speaking, a part of the interface ID number is a manufacturer's identifier and the remainder is left to the discretion of the manufacturer. In the IPv6, the interface ID is a part of the IPv6 address and can be freely decided by the manufacturer, which is different from the Ipv4. By making the interface ID correspond to a user ID, a sold terminal and customer information regarding that sale, can be coupled via the interface ID.
However, the correspondence between an interface ID and a customer varies. The variations result from changes in the customer's behavior, such as when the customer replaces a terminal. The resultant variation in the correspondence between the interface ID and the customer badly affects any applications which associate a user with an IP address. For example, in IP communications, correspondence data for indicating general names of an addressee and the IP address of an apparatus used by an actual addressee is stored as an address resolution mechanism. The service is provided based on the correspondence data.
However, when the correspondence between the interface ID and the user varies due to the replacement of the user's terminal by the user, the new terminal cannot be used for communication until the correspondence data is updated. The reason for this is as follows: packets are transmitted based on a prefix and a subnet number, but an IPv6-compliant apparatus determines whether or not the apparatus receives the packets by verifying the entire IPv6 address, including the interface ID, at the end of the transmission.
As described above, it is difficult to apply the IPv6 to applications requiring high availability such as mobile phones, when the correspondence between an interface ID and a customer is varied or is changed. Therefore, it is desirable to provide improved systems and methods for applying the Ipv6 when correspondence between interface ID's and customers vary or change.